Abstract:

The Taihangshan-Yanshan-West Liaoning orogenic belt is a Yanshanian(J—K)Au-Mo-Pb-Zn-Ag-Cu-Fe metallogenic belt, and also an important area of Yanshanian coal field in Eastern China. This paper  discusses the isotopic ages of both the eighteen ore deposits and ore related intrusive bodies of Yanshanian(J-K)time, the simultaneity, in general, of both the ore-deposits and the intrusions, as well as the association of the large coal field with the characteristic sedimentary formation, give a charonological constraint for the genetic relationship between the metallogenesis & coal-formation and the Yanshanian magmatic-tectonic events. Based on the Yanshanian magmatic-sedimentary-tectonic event sequence of this belt, in this paper, with adding the ages of both the ore-deposits and the coal field, a preliminary scheme of the Yanshanian magmatic-tectonic-metallogenesis event sequences is suggested. And then from the view of the composition, the genetic relationships between the ore-deposits and the intrusions and then the possible source of the ore deposits as well as the genetic relationships between the metallogenesis and coalfield and the orogenic episodes are discussed in this paper. During both the pre- and initial orogenic episode（J₁）and post-orogenic episode（K²₁）, both the neutral tectonics and the warm environment are considered as a good geodynamic setting for the formation of large coal fields. During the synorogenic episodes, the largescale magmatism is regarded to be a good geodynamic setting for metallogeneses. During the early orogenic episode（J₂）, both the andesitic magmas and the Au & Pb-Zn ore-deposits mainly are formed by the partial melting of the Archean lower crust. During the peak orogenic episode（J₃）, both the largescale granitic magmas and the Mo ore-deposits are generated from the intensive melting of the Archean upper crust. During the late orogenic episode(K¹₁）, the gabbro-monzodiorite & Fe ore-deposits and the monzonite-quartze monzonite & Cu ore-deposits are formed at the beginning of the temperature decreasing of the upper crust.

Key words: Yanshanian(J—K), Taihangshan-Yanshan-West Liaoning orogenic belt, magmatic-sedimentary-tectonic-metallogenetic event sequence, orogenic episode and metallogenesis